Local Wireless Network systems such as 802.11 operate in predefined spectrum such as the industrial, scientific and medical (ISM) bands. The spectrum allowed by cellular licensed devices and devices operating in unlicensed devices does not change over time. 802.11 devices operate in a contiguous spectrum channel. 802.11 devices operate in a contiguous spectrum channel.
In the United States, 408 MHz of spectrum from 54 MHz to 806 MHz may be allocated for TV. Currently, 108 MHz of that spectrum is being redeveloped for commercial operations through auctions and for public safety applications. The remaining 300 MHz of this prime radio spectrum may remain dedicated for over-the-air TV operations. However, throughout the United States, portions of that 300 MHz resource remain unused. The amount and exact frequency of unused spectrum may vary from location to location. These unused portions of spectrum are examples of Television White Spaces (TVWS).
TVWS described above is an example of an opportunistic band. An opportunistic band may allow unlicensed use of a spectrum by one or more unregistered systems, or secondary devices, but may reserve priority to registered systems/services, or primary users. However, current sensing technology cannot efficiently manage access to opportunistic spectrum by the registered or primary devices as well as unregistered or secondary devices. For example, it is desirable to simplify devices that are capable of operating as unregistered or secondary devices in an opportunistic band.